Exemplary embodiments pertain to the art of elevator systems and, more particularly, to a safety system for an elevator.
Elevators systems include a operational control and drive system (controller), motor, and brake that moves and stops elevator cars along a hoistway from just above a lower pit to an upper floor. The elevator system includes various safety devices typically arranged in a safety chain. The safety chain includes a number of safety devices whose output contacts are arranged in series. Some of safety devices are located near the elevator machine equipment, such as an over speed governor, while other devices such as switches and locks, are associated with elevator car doors, and still other devices are located in the hoistway, and pit. Typically the safety chain is linked to the control of power to the motor and brake. Activation of any device along the safety chain will cause the controller to disconnect the motor and brake from a main power supply. Power is required in order to lift the elevator brake. Therefore, activation of a safety device will apply the brake and remove power from the driving machine thus prohibiting motion of the elevator car.
Currently, the elevator system includes a controller located at or above the upper floor, typically in a mechanical room. Monitoring of the safety chain devices to facilitate repair or active bypass of a safety device to meet elevator safety codes requires discreet conductors that extend from each safety device in the safety chain to the controller. As such, a large number of wires extend to the controller from the pit along the hoistway, from the elevator car within a traveling cable, and often from intermediate floors.